1. Field of the Invention
The present invention relates to a cement composition which exhibits a reduced drying shrinkage and which has an air-entraining property which is less sensitive to environmental temperature.
2. Description of the Background
One of the major disadvantages of conventional cement, mortar and concrete is the tendency thereof to crack on drying due to the considerable drying shrinkage of the same.
To reduce such drying shrinkage, various admixtures, such as alcohol alkylene oxide adducts and alkylphenol alkylene oxide adducts as described in Japanese Patent Laid-Open No. 37259/1981 and Japanese Patent Publication No. 10947/1987, have been proposed.
However, these alkylene oxide adducts must be used in a large amount due to their limited performance and which is, therefore, quite expensive. Further, the air-entraining property of such adducts is affected by environmental temperature, which makes it difficult to prepare a mixture containing a prescribed amount of air content.
Hence, a need continues to exist for a cement composition whose air-entraining property is less sensitive to environmental temperature, and whose drying shrinkage is reduced to a low level. Additionally, a need also continues to exist for an inexpensive cement composition.